Two major areas of investigation are being carried out on this project. One relates to the role of the lysosomal systems in host and parasite in a selected number of fungal incited diseases of plants and animals. The diseases to be investigated are: The Spot Anthracnose of Desmodium, The Synchytrium Disease of Amphicarpon, Crytococcosis, Histoplasmosis, Sporotrichosis, and Candidiasis. Lysosomal activity is to be studies both by light and electron microscopy. Whenever possible, fluorescence microscopy with the use of acridine orange is to be employed in order to follow the activities of lysosomes in host and parasite. Modifications of the Gomori procesures are to be used for detecting at the fine-structure level acid phosphatase, alkaline phosphatase and arylsulfatase which are used as lysosomal markers. A second area relates to determining the occurrence and function of lysosomes in a selected number of fungal pathogens. The pathogens are: Cryptococcus neoformans, Histoplasma capsulatum, Sporothrix schenckii, Trichophyton mentagrophytes, Botrytis cinerea, Fusarium solani and Ceratocystis ulmi. The initial investigations are to be micrscopic. Those fungi showing a positive reaction for the presence of lysosomes are to be fractured to release these organelles which in turn are to be separated out by density gradient centrification. Their enzymatic contents are to be analysed biochemically. Following an accumulation of information, a lysosome concept for fungi is to be developed.